1. Field of the Invention
The present invention relates to the production of phenols and alkyl and/or alkenyl substituted phenols by the dearylation or cleavage of alkylenebisphenols and alkyltrisphenols. More specifically, the invention relates to the preparation of alkenyl phenol compounds such as p-isopropenylphenol and other related polymer products by carrying out the dearylation in the presence of hydrogen fluoride under mild conditions.
2. Description of the Prior Art
The dearylation of alkylenebisphenols such as bisphenol A, i.e., 2,2-bis(4-hydroxyphenyl) propane, has been carried out with acids or bases to yield p-isopropenylphenol and phenol. U.S. Pat. No. 3,466,337, for example, discloses the decomposition of bisphenol A by heating with an acid to form phenol and other products. The reaction is carried out at temperatures of 125.degree. C. to 300.degree. C. in the presence of an acid catalyst such as benzenesulfonic acid, toluenesulfonic acid, sodium hydrogen sulfate, phosphoric acid or benzenephosphonic acid. This method is also stated to be applicable to treatment of equivalent materials such as trisphenol, the product obtained by condensing isopropenylphenol with bisphenol. In U.S. Pat. No. 3,075,015, bisphenolic condensation products of phenols with aldehydes and ketones are split or dearylated under the influence of dilute aqueous solutions of alkali-metal hydroxides. European Pat. No. 0017852 discloses the cleavage of alkylenebisphenols and trisphenols to phenol and other by-products in the presence of hydrogen and a catalyst of nickel oxide, manganese oxide, and a metal oxide support. The reaction is carried out at temperatures of 250.degree. C. to 400.degree. C. While such acid or base-induced reactions may offer one or more advantages, all of these methods suffer the disadvantage of using harsh conditions of high temperatures and/or pressure. Accordingly, it is an object of this invention to provide an effective catalyst for the dearylation of alkylenebisphenols under mild conditions of temperature and pressure.